In recent years the concept of (wideband) code division multiple access (CDMA) has gained widespread international acceptance by operators active in the field of wireless communications. CDMA can significantly increase the capacity and the service quality and options of the networks when exploited by these operators.
One of the consequences of this development is the increase in interest in the planning and/or evaluation of radio networks in general and CDMA radio networks in particular. Radio planning and/or evaluation typically involve stages such as dimensioning, detailed capacity and coverage planning and/or network optimization. Radio planning is important for e.g. quick and accurate response to changes in e.g. traffic conditions or to cope with future traffic demands and as a consequence provides an operator with competitive advantages. An accurate planning can contribute to higher cost efficiency in operating radio networks. Moreover, it is important to be able to change the network configuration quickly and accurately when there is a health risk due to misplacement of base stations or incorrect configuration of base stations. The dimensioning stage in radio planning involves the estimation of the number and configuration of network elements, based, among others, on the operator's requirements and the radio propagation in the area. In the capacity and coverage planning stage, base station locations, configurations and parameters are determined in more detail on the basis of e.g. real propagation data and estimated user density and traffic. In the network optimization stage, the overall experienced network quality is assessed and improved, if necessary.
The method and system for downlink coverage planning and/or evaluation according to the invention can be used in the coverage planning stage of the radio planning and/or evaluation, and is particularly useful as an addition to an uplink coverage planning and/or evaluation.
At present the most popular and widely used method for the planning and evaluation of CDMA radio networks is a static Monte-Carlo simulation. This simulation involves the random generation of multiple network states defined by the number of users of the network and their positions. Users are generated a number of times. The multiple states are analyzed and the results of the analysis are evaluated. From the statistics results such as the maximum cell capacity and the cell coverage can be determined.
An important drawback of the Monte-Carlo and other simulations is the desired time to obtain reliable results. Moreover the known simulation methods do not possess the ability to quickly optimize a network or introduce a new site and see its effects on the downlink coverage of the radio network.